Pretty much. And people I did mentor wandered off after like 2-3 sessions (into which I put a ton of time), or they got a lot better during a project we worked

Pretty much. And people I did mentor wandered off after like 2-3 sessions (into which I put a ton of time), or they got a lot better during a project we worked on together, went off to do other projects, and a year later, I was correcting the exact same mistakes. As a mentor, you have to be really selective about your mentees (unless it's part of your job of course).